When you have to buy multiple plane tickets, you might be better off searching for just one ticket first. This will ensure you're seeing the lowest available price for a seat in the airline's computer system, according to Money Talks News.

Airline seats are grouped into price buckets. If you want to buy more than one ticket and, by unlucky chance, there's only one ticket left in the lowest price bucket, most airlines will quote you the price of both tickets in the higher bucket—rather than the available lower bucket seat and the next seat price available.

To save money, Jason Steele writes:

always specify one traveler until you find the lowest price. Then, search again with the actual number of travelers and see if the price changes. If it does, you can always book one seat at the lower price and make a separate reservation for the others at the higher price.

Note that this trick also works for booking award seats at the lowest mileage levels.

Of course, you may want to also check that the seat in the lower price bucket is near or next to the seat in the higher bucket, but when buying tickets for groups or if sitting next to each other doesn't matter, it may be worth the effort to check for single seats first.

Check out the full article for more ways to save money when booking your flight, including avoiding a Delta-like computer glitch that penalizes customers when they're logged in.